One of the problems in the field of satellite mobile links is how to produce compact antennas with dual polarization intended to be positioned on a mobile vehicle, and offering a high efficiency at the link level and a high gain.
In general, to have antennas of compact dimensions, “flat” forms are given preference and the antennas consist of radiant elements, better known as “patches”, which are powered in order to obtain electronic scanning.
FIG. 1 represents a general architecture of an antenna consisting of a polarizer 1, a radiant panel 2 and an electronic module 3. The radiant panel comprises antenna elements that can take different forms.
FIG. 2 schematically represents a first exemplary embodiment according to the prior art, in which the radiant panel 2 comprises a number of antenna elements 4i and two parallel power supply distribution networks 5, 6. A first connector 7 is used to supply power to the panel with a horizontal polarization for example, via the network 5, and a second connector 8 is used for its power supply in vertical polarization mode. In this way, the antenna is supplied with power in a dual manner, horizontal polarization and vertical polarization. This network of parallel type takes the form of a binary tree of a number of lines Li of chosen impedances. Such a type of network presents the drawback of being bulky, and cannot therefore be produced on the same set of substrates as the patch-type radiant elements.
Since the concepts of horizontal polarization and vertical polarization are known to those skilled in the art, they will not be detailed in this description.
FIG. 3 represents another exemplary embodiment of an antenna according to the prior art which implements a series-type assembly, in other words one with the antenna elements all mounted in series. There is still a first connector 9 providing for the power supply for the antenna elements for a horizontal polarization, and a second connector 10 allowing for a vertical polarization of the antenna elements. The series network consists of a single set of lines of chosen impedances. The figure respectively represents a first series network 11 and a second series network 12. Such a type of network presents the advantage of having little bulk and of being able to be produced on the same set of substrates as the substrate on which the radiant elements are arranged. This antenna does, however, present the drawback of being of low bandwidth when the network is of large size. Also, the impedances of the lines lead to geometries that are often unfeasible.